294 Natural-Historical Collections. 
volume of the olfactory lobes of the brain. ‘The extent which is required in the 
ethmoid, is the occasion, according to M. Geoffroy, of the restricted size of the 
anterior sphenoid, rendering it, at the same time, smaller, and more dense, and 
preventing the frontal bones, both from contributing to form the arch of the 
orbit, and from extending over the cerebral lobes. 
M. Geoffroy, who adopts the opinion that the optic nerve is not in the cra- 
nium, thinks, nevertheless, that this nerve exists at the side of the eye; but that 
not being able to penetrate the cranium by the ordinary passage, obstructed by 
the compression of the sphenoid, it is obliged, to use the words of the author, 
to take the nearest road, and this nearest road is by the trunk of the fifth pair. 
It is, he adds, a disposition, which although propagable by generation, is not 
the less to be considered as monstrous: a sort of analogy is observable between it 
and those monsters, in which the hypertrophy of an organ produces atrophy in 
the neighbouring parts. 
Besides, it is a remarkable fact, and directly contrary to mere than one theory 
on the speeial functions of the different lobes of the encephalon, that the lobes 
which have been lately called the optic lobes, are in the mole rather above than 
below the proportional size, which they attain in those animals, whose vision is 
most perfect. 
Naturalists have been embarassed by another difficulty no less serious in the or- 
ganization of the mole, namely, how it brings forth its young ; for the feetus, very 
large in proportion, considerably exceeds the dimensions of the pelvis, and its 
passage would be so much the more impracticable as the ossa innominata are un- 
ited most intimately to the sacrum ; but these bones are not joined to each other 
at the symphysis pubis, so that the rectum, the vagina, and the urethra, (which, 
in the female mole, has an external orifice independent of that of generation), 
have not to traverse the pelvis, but are placed below, cr rather in that kind of 
groove which is left by the separation of the pubic bones. ‘The pelvis does not 
then, in any degree impede the progress of the fetus, which, passing as usual 
through the vagina, obtains egress by dilating the vulva, there being no osseous 
apparatus to prevent it. This explanation, advanced some years since by M. 
Breton, a skilful naturalist of Grenoble, was sufficiently satisfactory, and M. 
Geoffroy takes advantage of it in explaining the disproportion which is found 
in the mole between the organ of vision and that of smell. In ordinary ges- 
tations, the former is developed; the latter, on the contrary, is less than in 
the adult state. A prolonged gestation must therefore favour the organ of smell ; 
and those foetuses which remain a sufficiently long time in the uterus to acquire 
a size proportionate to that of the mole, should have large nostrils and small 
eyes. 
The author has discovered, under the lumbar vertebre of this animal, eight 
little supplementary bones, which prevent this region from bending, and give to 
the loins the necessary strength for raising and removing the soil under which it 
lives. He has remarked an equally;curious fact, that till the age of six months, the 
mole has its vagina closed by a sort of hymen, but complete and without opening, 
so that, prior to this period, there is great difficulty in distinguishing the males 
from the females. A little conical and sharply pointed bone, with which the 
penis is provided at its extremity, seems destined to overcome this obstacle. The 
urethra of the female passes through the clitoris exactly as it passes through the 
penis in the male; and in the latter the bladder opens into a pouch where the 
vasa deferentia also terminate, in a sort of vesicula seminalis. 
On the habits of the mole, our author enters into details no less interesting 
than on its anatomy. A mole-catcher, named Lecourt, already well known ton a- 
turalists by his observations published by the late M. Cadet Devaux, had con- 
trived the most ingenious means of following with the eye the motions which the 
mole makes under the soil, and he states, that when it is frightened, it moves 
with a surprising rapidity from one point of its burrow to another. He goes so 
far as to say that this animal, which crawls with so much difficulty upon the 
Surface, runs below with a gteater speed than a galloping horse. ‘This great 
